1. Field
Methods and apparatuses consistent with the present disclosure relate to decoding bitstreams and, more particularly, to restoring an original audio signal by decoding a bitstream including an audio signal.
2. Description of the Related Art
An audio decoder restores a sound-reproducible audio signal by receiving an audio bitstream and decoding the received audio bitstream. The audio bitstream may be generated by encoding an audio signal according to a predetermined standard, such as a Moving Picture Experts Group-1 Layer-3 (MP3) standard. In this case, the audio decoder is an example of an MP3 decoder. In addition, the restored audio signal may be a stereo signal or a multi-channel audio signal.
The MP3 decoder uses Pseudo Quadrature Mirror Filter technology. The MP3 decoder synthesizes a decoded audio signal so as to be an original multi-channel audio signal. The MP3 decoder also processes a restored bitstream in a time domain. In addition, the MP3 decoder synthesizes the restored bitstream so as to be a multi-channel audio signal by using a complicated operation, such as convolution.
Thus, since complexity of the operation performed by the MP3 decoder is very high, a large-capacity memory and a high-performance processor are required for high-speed operation. In addition, since the MP3 decoder processes a restored bitstream in the time domain, the MP3 decoder is not compatible with a multi-channel codec for processing a bitstream in a transform domain.